Micromechanical components which are used in the automotive field, as inertial or acceleration sensors, for example, normally have a micropattern having movable functional elements. The micropattern is also designated as a MEMS structure (microelectromechanical system). During the operation of such sensors, the deflection of a functional element is detected, for instance, by a change in the electrical capacity compared to a fixed reference electrode.
Usual methods for producing a micromechanical component include forming the micropattern on a functional substrate (sensor wafer) and connecting the functional substrate to a cap substrate (capping). A cavity is formed, in this manner, which encloses the functional element, whereby the functional element is sealed hermetically from the environment. A specified gas atmosphere or pressure atmosphere may also be set in the cavity.
One method for capping a functional substrate is discussed in German document DE 10 2007 044 806 A1. In this method, the cap substrate is developed to have a projecting, tenon-shaped patterned element. The functional substrate is provided having an opening, which functions as a counter-pattern for the projecting patterned element of the cap substrate. The two substrates are connected so that the tenon-shaped pattern of the cap substrate engages in the opening of the functional substrate, and in this manner a sealing region encircling the micropattern is formed. Furthermore, a connecting medium is inserted into the sealing area, so as to produce a hermetically sealed connection. In this instance, the use of Sealglas is suggested, which is applied onto the conical pattern with the aid of a silk-screen mask before producing the connection with the functional substrate.
One development that may be observed in microsystems technology is the increasing miniaturization of the components. This brings about the tendency, besides the functional patterns, of also embodying the connecting areas (connecting frames and bonding frames) of micromechanical components to be smaller and narrower. The application of Sealglas, described above, with the aid of a silk-screen mask in this instance, however, increasingly bumps up against limits and therefore seems unsuitable for satisfying the (future) miniaturization requirements. In addition, the opening, developed on the functional substrate according to German document DE 10 2007 044 806 A1, has a rectangular shape in cross section, which may bring about the problem of insufficient adhesion.